1. Field of the Invention
This invention relates, in general, to prostheses which are externally attachable to severed or amputated limbs and, more specifically, to apparatus for use in attaching prostheses to limbs.
2. Description of the Prior Art
It is common to attach a prosthesis or artificial limb externally onto a limb of an individual which has been amputated or otherwise severed in order to provide a measure of use of the limb to the individual. Typically, a strap and harness assembly is utilized which engages the stump of the limb. During use of the weight bearing limb, such as a leg or arm, forces are generated which are transmitted through the prosthesis directly to the flesh surrounding the stump. Since it is difficult to insure a secure, non-slip engagement between the prosthesis and the stump, the forces generated during use of the prosthesis create movement of the prosthesis relative to the stump which results in irritation of the flesh surrounding the stump and discomfort to the wearer which makes it difficult, if not impossible, to effectively use the prosthesis in a normal manner.
One solution to the above-listed problems is set forth in U.S. Pat. No. 3,947,897. In this device, a socket is inserted directly into a cavity of the bone at the end of the stump. The prosthesis is contoured to the shape of the stump and includes a lock pin insertable within the socket for releasably mounting the prosthesis to the socket and stump.
As shown in U.S. Pat. Nos. 2,578,019 and 3,186,006, it has also proposed to employ cushions or pads which are disposed between the end of the stump and the prosthesis to absorb and cushion some of the forces and pressures transmitted from the prosthesis to the stump.
While the above-described devices reduce to a certain extent some of the forces transmitted to the stump and thereby ease some of the discomfort typically encountered with the use of a prosthesis, such devices fail to evenly distribute the forces over the entire end of the stump such that directional forces still cause pressures to be exerted on the stump resulting in discomfort to the user.
Thus, it would be desirable to provide an amputation apparatus which overcomes the problems of previously devised devices for use with a prosthesis attached externally to a severed or amputated limb. It would also be desirable to provide an amputation apparatus which evenly distributes the forces exerted by the prosthesis over the end of the stump to reduce the discomfort caused by such forces. Finally, it would be desirable to provide an amputation apparatus which is available in a variety of sizes for use on different size individuals, from adults to children, and also to allow for bone and/or flesh growth and changes in the shape and size of the limb itself.